image.bats: add tests to exercise manifest list support
image.bats: add tests to exercise manifest list support

Test that we can pull an image using a tag that resolves to a manifest
list, or by the digest of a manifest list, and then query it using
either the list's manifest's digest or the digest of the manifest of the
arch-specific image from the list which we'd expect the image library to
select.

Signed-off-by: Nalin Dahyabhai <f562fcb2a0b898bf0be1afc867ea92325d8f825f@redhat.com>

nalind/cri-o,mikebrow/cri-o,mikebrow/cri-o,mikebrow/cri-o,kubernetes-incubator/ocid,kubernetes-incubator/cri-o,mikebrow/cri-o,kubernetes-incubator/ocid,nalind/cri-o,kubernetes-incubator/cri-o,kubernetes-incubator/cri-o,kubernetes-incubator/ocid,nalind/cri-o,kubernetes-incubator/cri-o